A. C. Nielsen Co. has had an effective monopoly in measuring national TV audiences, but it does compete with Arbitron Ratings Co. in measuring local TV stations. The main systems of measurement are:

Nielsen Television Index. This system, started in 1987, consists of 4,000 people meters in homes around the country. The people meter records information supplied by viewers on who is watching which program; it then delivers that data the next day to the network and advertiser. A household stays in the sample an average of two years.

Nielsen Station Index. NSI measures local television viewing by two methods. The first, which uses about 400 meters on TV sets in each of 24 markets, simply reports which channel is turned on. A set meter stays in a home for five years. The second method, which collects information about who is watching specific programs, uses 200,000 diaries sent out four times a year to 211 markets. The quarterly diary measurements are commonly known as “the sweeps.”

Arbitron Local Market Report. This system, operated by Arbitron Ratings Co., competes with Nielsen in the measurement of local TV stations. Like Nielsen’s NSI, Arbitron collects its information from both set meters in 13 markets and 100,000 diaries sent to 209 markets as least four times annually.


Arbitron ScanAmerica. This system, currently operating in 600 homes in Denver, is Arbitron’s plan to compete with Nielsen in the national ratings game. Based on people meter technology, the system also seeks to trace product purchasing habits with TV viewing. Arbitron is two years into a five-year, $125-million plan to put ScanAmerica into 5,000 homes by 1992.

Pergamon AGB. The British ratings company lost $67 million when it first tried to introduce its people meter in the United States in 1987-88. Now owned by Robert Maxwell, AGB hopes to exploit the current uncertainty surrounding Nielsen to stage a comeback. Network executives who have met with AGB representatives said the company has offered few specific ideas about its plans.